The present invention is directed generally to an improved automatic vehicle distance control system and method.
According to the article titled “Intelligent Tempomats Maintain Distance,” published in VDI-Nachrichten, 3 Sep. 1999, 35, page 20, distance control Tempomats (cruise-control systems) and automatic lane recognition are typical assist systems that will soon be available in trucks and buses. If, in a vehicle equipped with such automatic distance control capabilities, the distance from a vehicle driving in front becomes shorter than a preset safe distance, various braking devices are automatically actuated. For example, the retarder may be actuated, or the service brake may be used (which acts on all vehicle wheels).
Vehicles having service brakes that can be automatically actuated are usually equipped with electronically controlled brake systems (EBS). For vehicles equipped with conventional brake systems, including anti-lock brake systems (ABS), and anti-slip regulation systems (ASR), however, the brakes cannot be actuated directly by an external signal or by an action not initiated by the driver. Such brake systems must be modified for this purpose, which can involve adding components, including additional solenoid valves, with associated undesired increases in vehicle complexity.
Accordingly, it is desired to provide a vehicle equipped with a conventional ABS/ASR and automatic distance control with the capability of at least partial automatic actuation of the service brake in operation of the automatic distance control function, without undue complexity.